2004 Annual Report for LNC03-237
Nutrient Management Planning for Dairy Farms Practicing Management Intensive Rotational Grazing
Summary
Data needed to estimate dry matter intake and manure production on seven Wisconsin dairy farms was collected in the summers of 2003 and 2004. Dry matter intake from pasture varied from 10 lbs/cow/day to over 40 lbs/cow/day with an average of 18 lbs/cow/day. Milk production averaged 52 lbs/cow/day. Manure production estimates based on these values ranged from 93 to 114 lbs/cow/day with an average of 105 lbs/cow/day. This is significantly less than values currently used for nutrient management planning for cows in confinement.
Objectives/Performance Targets
Producers using Management Intensive Rotational Grazing (MIRG) will increase their awareness of the need for Nutrient Management Planning (NMP) and will become more knowledgeable of what is required to develop accurate plans.
Other audiences (agencies and private consultants) involved in the process will be more knowledgeable about NMP issues for grazing farms and improve their ability to assist/support the NMP process.
Accuracy of estimates of manure production by grazing dairy cows will be improved to facilitate NMP by MIRG farms.
Nutrient management plans for the participating farms will be developed, implemented, and monitored to demonstrate to the NMP process to other MIRG farms.
Development and demonstration of a nutrient management planning framework which will enable grazing dairy farms in the north central region to meet current and future nutrient management standards.
Development/modification of supporting NMP software and related tools that provide farmers and their support network with a means for accurately planning and documenting nutrient flows throughout the farm in accordance with nutrient management standards.
MIRG farms in the North Central Region will develop and implement nutrient management plans that enhance their environmental stewardship and improve the natural resource base on which they depend.
Accomplishments/Milestones
Data was collected form seven farms in both 2003 and 2004. Data collected included pasture dry matter availability before a grazing event and after a grazing event. This data provided information on dry matter intake. Pasture quality was measured by taking grab samples at each sampling time. Milk production was also measured during the time that animals were in each sampled pasture. Data was collected three to five times each season on each farm. This provided a total of 46 individual measurements in 2003 and 30 in 2004 for a total of 76 for the first two years of the study. Manure was sampled five times at each farm to provide average nutrient content. Supplemental feed levels and quality were also recorded. Information on total intake levels of P and N and total P and N excreted in milk allowed us to estimate manure production required to excrete the remaining P and N.
In 2003, average crude protein levels of pasture samples was 20%, average neutral detergent fiber level was 45%, and average relative forage quality value was 187. Pasture dry matter intake averaged 12 lbs/cow/day. Average milk production was 52 lbs/cow/day. Manure nitrogen content was 7.8 lbs/ton and P2O5 averaged 6 lbs/ton. Using these values, average manure production was estimated to be 93 lbs/cow/day based on nitrogen excretion and 75 lbs/cow/day based on P2O5 excretion. Both of these values are well below the 148 lbs/cow/day currently used to estimate manure production of 1400 lbs cows.
In 2004, pasture quality levels were similar to 2003 with an average crude protein level of 21%, average neutral detergent fiber level of 44%, and average relative forage quality of 209. Pasture dry matter intake averaged 24.5 lbs/cow/day. Average milk production was 52 lbs/cow/day. Manure nitrogen content was 10.5 lbs/ton and P2O5 averaged 7.9 lbs/ton. Manure production was estimated to be 118 lbs/cow/day using P2O5 excretion and 135 using nitrogen excretion. Averaged over the two years of the study, manure production was 96 lbs/cow/day using P2O5 excretion and 114 lb/cow/day using nitrogen excretion. Both of these values are well below the 148 lbs/cow/day currently used to estimate manure production of 1400-lb cows. There was significant variability in the 2004 data, however, and these results should be considered preliminary until the final year of the study is completed in 2005.
Impacts and Contributions/Outcomes
Information generated from this project was incorporated into five grazing schools held in Wisconsin in 2003 and 2004. Results were presented at the 2004 Upper Midwest Grazing Conference in LaCrosse, WI and the Central Wisconsin Grazing Network Annual Conference in Marathon, WI. An article summarizing some of the results appeared in the Winter 2004 issue of Forage Focus, a publication of the Midwest Forage Association. A meeting of all participants was held at Wisconsin Dells in March 2005. Results obtained thus far were presented and discussed.
The project is providing participating producers information regarding dry matter intake of their cows on pasture. It also is providing pasture utilization percentages, milk production figures, and pasture quality values. These types of values have not previously been available and are being shared with others as representative of typical grazing dairy farms. At the conclusion of the project, this information will represent a unique and valuable database for grazers in the north central region.
The ultimate goal of this project is the development of meaningful nutrient management methodology for grazing dairies. The manure generation estimates are fairly consistent but one additional year of data collection (2005) will help solidify the values that we already have.